1. Field of the Invention
This invention relates generally to fluid flow control valves. More particularly, this invention relates to valves wherein a membrane or "curtain" is employed to seal a plurality of orifices in a valve orifice block against fluid flow.
2. Description of the Prior Art
In fluid flow control systems, it is frequently necessary to employ a valve which is resistant to cavitation damage in the case of liquid throttling, or resistant to the generation of aerodynamic noise in the case of gas throttling. One type of valve having these characteristics is the curtain valve, in which a flexible membrane, or curtain, is employed to uncover or cover orifices in a valve orifice block, and in which the orifices are parallel to and in line with the valve outlet so as to provide a straight-line flow path through the valve. In such a valve, a flowing fluid does not impinge on valve parts to an appreciable extent during the throttling process by virtue of the straight-line path which it follows when leaving the valve orifices.